| 摘要 |
PURPOSE:To make it possible to miniaturize and highly integrate cells and also effectively prevent the punch-through phenomenon by forming the third semiconductor layer of reverse conductive type with lower density of impurity than that of the first semiconductor layer deeply. CONSTITUTION:A semiconductor film 6 is formed on the first insulative film 5a formed on the main surface of a semiconductor substrate and is underetched to form a semiconductor film pattern 6, and an overhang-shaped mask is formed at the same time. Then, reverse conductive type ions with low density are deeply implanted into the substrate through the overhang-shaped mask so as to deeply form the reverse conductive type, third semiconductor layer 11, and further, reverse conductive type ions are shallowly implanted with the pattern 6 as a mask to shallowly form the first conductor layer 4. And one conduction type ions are implanted to form the one conduction type, second semiconductor layer 8. The second insulation film 5d is formed, and an opening 10a is selectively formed to partially expose the first semiconductor layer 4 and the second semiconductor layer 8 so that a metallic electrode film 9 is formed. |
